Phthalide → Indeno(1,2-c)isochromene-5,11-dione

HRID 1052141Notes

Reaction equation

HRID 1052141 reaction equation
C[O-].[Na+].[C:4]([C:7]1[CH:14]=[CH:13][CH:12]=[CH:11][C:8]=1[CH:9]=[O:10])([OH:6])=O.[C:15]1([C:24]2[C:19](=[CH:20][CH:21]=[CH:22][CH:23]=2)[CH2:18]O1)=[O:16]>C(OCC)(=O)C>[CH:20]1[C:19]2[C:18]3[C:9](=[O:10])[C:8]4[CH:11]=[CH:12][CH:13]=[CH:14][C:7]=4[C:4]=3[O:6][C:15](=[O:16])[C:24]=2[CH:23]=[CH:22][CH:21]=1

Participants

5

Reactant 3

HCID 6885PhthalideHCID 8406Phthalaldehydic acidHCID 10942334Sodium Methoxide

Product 1

HCID 265728Indeno(1,2-c)isochromene-5,11-dioneYield 86%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Conditions

Temperature
65 °C

Procedure

Sodium methoxide (40 mL of a 4 M methanolic solution) was added to a solution of 2-carboxybenzaldehyde 1d (1.000 g, 7.455 mmol) and phthalide 2d (1.119 g, 7.455 mmol) in ethyl acetate (20 mL). The solution was heated at 65° C. for 18 h, concentrated, and acidified with concd HCl. The resulting mixture was diluted with benzene (125 mL), TsOH (100 mg) was added, and the solution was heated for 7 h at reflux in a flask affixed with a Dean-Stark trap. The solution was cooled to room temperature, concentrated, diluted with CHCl3 (150 mL), and washed with sat NaHCO3 (3×50 mL) and sat NaCl (50 mL). The organic layer was dried over sodium sulfate and concentrated to provide indenobenzopyran 4d as an orange solid (1.583 g, 86%): mp 258-259° C. (published mp 257° C.). 1H NMR (CDCl3) δ 8.40 (d, J=8.56 Hz, 1H), 8.32 (d, J=7.93 Hz, 1H), 7.84-7.79 (m, 1H), 7.61-7.39 (m, 5H). Additional details regarding the synthesis of compound 8 are found in Pailer et al., Monatsh Chem., 92:1037-47 (1961), the synthetic disclosure of which is incorporated herein by reference.

Workup

  1. concentrationconcentrated
  2. additionThe resulting mixture was diluted with benzene (125 mL), TsOH (100 mg)
  3. additionwas added
  4. temperaturethe solution was heated for 7 h
  5. temperatureat reflux in a flask
  6. temperatureThe solution was cooled to room temperature
  7. concentrationconcentrated
  8. additiondiluted with CHCl3 (150 mL)
  9. washwashed
  10. dry with materialThe organic layer was dried over sodium sulfate
  11. concentrationconcentrated

Sources & evidence

ORD record
ord-b9e4535f46264ac7996e28e44b5f190b
Source dataset
uspto-grants-2016_07
Patent number
US09388211B2

Reaction notes

Loading…